The infected bees would abandon their hives and congregate near outside lights, moving in increasingly erratic circles on the ground before dying.

In order to better understand how the parasitic fly affects the bees’ behavior, the team built a system to track the movements of infected bees in and out of a hive. Each bee has a set of tiny radio frequency trackers attached to the top of its thorax.

When the bees leave and return to the hive, they come back through a small tube outfitted with dual laser readers that interact with the individual trackers.

The readers create “virtually a 24-hour record of bees going in and out of the hive to forage,” Christopher Quock, a San Francisco State University master’s biology student working on the hive’s design together with bee keeper Robert MacKimmie, said in a statement.

Knowing when the bees leave and come back is important for understanding how and when the parasites might cause the bees to abandon their hives.

The original study found bees disoriented and dying at night, but the researchers aren’t sure whether the infected bees only leave their hives to fly in the dark.

Quock’s challenge has been to create a specialized hive design where the bees “still have room to do their normal behavior.”

He said in order to get their unique identification and time stamp for each bee, the insects have to pass one at a time under the laser readers through a narrow passage.

“Hopefully in the long run, this information might help us understand how much of a health concern these flies are for the bees, and if they truly do impede their foraging behavior,” Quock said in the statement. “We also want to know whether there are any weak links in the chain of interactions between these flies and honey bees that we could exploit to control the spread of this parasite.”

Andrew Zink, SF State assistant professor of biology and Quock’s advisor, said the tracking project might eventually shed light on how the infected bees behave inside the hive.

“We are also interested in knowing if parasitized foragers are the recipients of aggression by other workers, for example if they’re expelled from the hive, or if parasitized foragers behave in ways that disrupt hive productivity,” Zink said in the statement.

He said that if enough of the infected bees do the wrong dances to send uninfected foragers off in the wrong direction for food, the hive’s productivity could go under.

Professor of Biology John Hafernik, who first discovered the zombie-bee phenomenon, said the radio tracking study could help give researcher “a hint” as to why parasitism alters bee behavior.

“It might just be that having a maggot in the back is uncomfortable,” he said in a statement.